Health-related issues of people experiencing homelessness in Thailand: a scoping review

Introduction Homelessness is a significant global challenge affecting people worldwide. In Thailand, the health-related issues of people experiencing homelessness have not been a major research focus. This scoping review aims to explore the scope of research on health-related issues among people experiencing homelessness in Thailand. Methods Eight databases (ACI, AMED, Embase, PsycINFO, PubMed, Scopus, TCI, and Web of Science) were searched from inception of each database to August 2022. The search terms consisted of terms related to people experiencing homelessness in Thailand. Research articles published in Thai or English were included. Results Of 186 articles, 167 were excluded during duplicate removal (n = 45), title and abstract screening (n = 106), seeking for full-text articles (n = 2), and full-text screening (n = 14). Nineteen articles were included for extraction and synthesis. Three topics (health status, causes of homelessness and effects of homelessness on health, healthcare and social services) were summarised. The included studies described mental health (e.g., depression, suicide, alcohol and drug dependence), physical health (e.g., poor self-hygiene, injuries, accidents), and health behaviours (e.g., alcohol drinking, substance use, unsafe sex). Social behaviours and health problems linked to homelessness, and several factors related to health and living conditions (e.g., stigma, discrimination) were reported. People experiencing homelessness had some barriers to access to healthcare and social services (e.g., health insurance, social welfare, financial difficulties). Conclusions The majority of studies on health-related issues in people experiencing homelessness in Thailand are descriptive studies. Future studies should focus on the interactions and mechanisms between homelessness and health.


INTRODUCTION
Homelessness is a serious violation of human dignity and has become a global issue.It affects people with different backgrounds across the world (United Nations, 2020).According to the United Nations (UN)-Habitat 2015, 1.6 billion people lived with inadequate housing (Kassim et al., 2015).The data in the US showed 580,466 people experienced homelessness in 2020 (70% lived alone and 30% lived with their families) (National Alliance to End Homelessness, 2022).In the European countries, at least 700,000 people experienced homelessness; this number reflected a 70% increase in the past decade (FEANTSA, 2019; World Health Organization & Regional Office for Europe, 2020).
It is known that people experiencing homelessness have higher risks of developing several health problems, compared with other populations (Institute of Medicine (US) Committee on Health Care for Homeless People, 1988).Several health-related issues are highlighted among people experiencing homelessness, including infectious diseases (e.g., HCV, human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS)), non-communicable diseases (e.g., diabetes, hypertension), musculoskeletal disorders (e.g., chronic pain), dental health, mental disorders (e.g., depression, anxiety, suicide), childhood trauma, and substance use (e.g., alcohol, methamphetamine) (Mc Conalogue et al., 2021;Oppenheimer, Nurius & Green, 2016;Australian Bureau of Statistics, 2016).These health issues are considered as causes and consequences of homelessness.
More than 4,500 people experiencing homelessness were reported in Thailand (Royal Thai Government, 2022).A previous survey reported that a majority of people experiencing homelessness were males (86%) and 40-59 years old (57%) (Community Organizations Development Institute, 2020).More than half lived in the capital city, Bangkok, and major provinces across the country (Community Organizations Development Institute, 2020).Studies in Thailand reported some health-related issues among people experiencing homelessness.Nicotine addiction (Pitukthanin et al., 2016), violence, physical and sexual abuse (Farley et al., 2004;Techakasem & Kolkijkovin, 2006), and sexual transmitted infection (e.g., HIV/AIDS) (Houysai, Rutchanakul & Kongvattananon, 2015;Narongsakputi, Ratchanakul & Nirattaradol, 2018) were reported as common physical health issues.While psychotic disorders, alcohol dependence, and major depressive episode were identified as major mental health issues (Farley et al., 2004).Thai citizens have been eligible for preventive, curative, and palliative services under the universal health coverage scheme since 2002 (Sumriddetchkajorn et al., 2019;Wattanapisit & Saengow, 2018).However, a survey indicated that people experiencing homelessness had limitations to access to healthcare services (Pitukthanin et al., 2016).
To the best of our knowledge, people experiencing homelessness in Thailand are a minority and less privileged.Studies on health-related issues among this population are not mainstream research in the country.Health-related issues were explored in some studies in the field of social sciences; however, they were not the main research topics.This raises an important question regarding the scope of studies on health-related issues among people experiencing homelessness.This scoping review aims to explore characteristics and scope of studies on health-related issues of people experiencing homelessness in Thailand.

MATERIALS AND METHODS
This scoping review was conducted and reported following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for scoping reviews (PRISMA-ScR) (Tricco et al., 2018).

Search methods
A systematic search was performed in eight databases, include the Allied and Complementary Medicine Database (AMED), ASEAN Citation Index (ACI), Embase, PsycINFO, PubMed, Scopus, Thai-Journal Citation Index (TCI), and Web of Science.The search included articles from inception of each database to 9 th August 2022.The search terms related to people experiencing homelessness in Thailand: (homeless OR homelessness OR houseless OR roofless OR unhoused OR "rough sleeping") AND (Thailand OR Thai) were adapted to each database's command language.For the ACI and TCI databases, only the search terms for homelessness (not including Thailand) using the Boolean 'OR' were searched due to a limitation of the databases.The Thai words for homelessness (i.e., rai-ban, rae-ron) were searched in a TCI search.Articles found from the databases were transferred to Endnote X9 citation manager (Clarivate, Philadelphia, PA, USA).

Study selection and eligible criteria
After the duplicate removal, two authors (AW and TS) independently screened titles and abstract.Any disagreement was reviewed by another author and resolved through consensus.The authors (AW and TS) reviewed full-text articles for eligibility based on the following inclusion and exclusion criteria.A full-text article was included if: (i) the article related to health-related issues of people experiencing homelessness in Thailand and (ii) the article was published in the English or Thai languages.A full-text article was excluded if: (i) the article was a non-empirical study (e.g., systematic review, scoping review, narrative review), conference abstract, book or book chapter, and (ii) the article focused on homelessness due to criminal justice (e.g., prison).

Data extraction and synthesis
The two authors (AW and TS) extracted information, including, title, author names, publication year, language of publication, study design and data collection, participant and setting, outcome measurement, and results, from the included articles.The information was recorded in the data extraction form (Box 1).The authors synthesised the articles to summarise topics on health-related issues among people experiencing homelessness.

RESULTS
Of 186 articles retrieved from the eight databases, 45 duplicates were removed.One hundred and six articles were excluded during the title and abstract screening.Two full-text articles were not available on journals' websites, and fourteen articles were excluded after the full-text screening.A total of 19 articles (19 studies) were included for analysis (Fig. 1).

Characteristics of the included studies
Of 19 studies, 13 studies (68.4%) were published in Thai and six studies (31.6%) were in English language.Seventeen studies (89.5%) were published in the past decade (2014)(2015)(2016)(2017)(2018)(2019)(2020)(2021)(2022), and two studies (10.5%) were published before 2010 (2004 and 2006).Six studies (31.6%) employed a qualitative design, and three studies (15.8%) were cross-sectional studies.Five studies (26.3%) focused on children and adolescents.Nine studies (47.4%) were conducted among staff or officers who work with people experiencing homelessness.Of the nine studies involved officers, five studies included people experiencing homelessness as study participants.One study (5.3%) was conducted in nine countries, including Thailand.The rest of the studies (n = 18, 94.7%) were conducted in Thailand only.Eight studies (42.1%) were conducted in the capital city.A variety of study designs (e.g., cross-sectional study, experimental study, qualitative study, mixed methods study, action research) was conducted.Most studies were descriptive studies.Table 1 shows the summary of the included studies.Three topics were summarised from the included studies.

Topic 1: health status
Various health conditions, including mental health, physical health, and health behaviours were reported.One study showed 36.7% of people experiencing homelessness rated their health status as bad, while about half (46.7%) perceived their health status was acceptable (Viwatpanich, 2015).
Severe psychiatric disorders were associated with higher risks of suicide and multiple psychiatric disorders (Awirutworakul et al., 2018).
Physical health issues such as musculoskeletal pain, tuberculosis, respiratory diseases, skin diseases, poor self-hygiene, injuries, and accidents were commonly found among older adults experiencing homelessness (Viwatpanich, 2015;Khutkhong et al., 2020).A study in 468 people experiencing homlessness who had dental check-ups found 97.3% had  The centre for the protection of the defenceless was the main agency as a screening unit, analysing problems, evaluating target groups, and coordinating referrals to relevant agencies Note: 95%CI, 95% confidence interval; DM, diabetes mellitus; DSM-IV, diagnostic and statistical manual, fourth edition; ICD-10, international classification of disease, tenth edition; MINI, mini-International Neuropsychiatric Interview; OR, odds ratio; NGO, non-governmental organisation; PTSD, post-traumatic stress disorder; STI, sexually transmitted infection.
A study on adolescents experiencing homelessness' sexual behaviour showed that 57.28% had multiple sex partners and 12.62% experienced pregnancy or involved in pregnancy of their partners (Narongsakputi, Ratchanakul & Nirattaradol, 2018).Other health-related behaviours such as alcohol drinking, substance use, and poor self-hygiene were reported in the studies (Muannadon et al., 2019;Khutkhong et al., 2020).

Topic 2: causes of homelessness and effects of homelessness on health
Social behaviours and experiences linked to homelessness.A cross-sectional study conducted among people in prostitution found that 57% experienced current or past homelessness (Farley et al., 2004).Compared to youth who live with their families, youth who left homes were more likely to child neglect, sexual abuse, rejection, poverty, and being in custody (Techakasem & Kolkijkovin, 2006).Another study found that children and youth experiencing homelessness were more likely to have family poverty and a lack of close-knit family (Khongmueang, Ekakun & Nilmoje, 2017).Reasons for leaving home among children included family problems (such as breakdown and poverty), substance use, and attachment to their peers (Muannadon et al., 2019).A study conducted in older adults found that health problems and disabilities were common causes of permanent homelessness (Viwatpanich, 2015).Cognitive problems and mental illnesses were identified as the main reasons of being homeless in one study (Khutkhong et al., 2020).
Several factors related to health and living conditions were reported among people experiencing homelessness.A study reported that having extra daily meals had a positive effect on happiness, while smoking led to a negative impact on happiness (Tangtammaruk & Chaiwat, 2019).Homelessness affected living patterns related to health (e.g., hygiene, physical abuse, sexual abuse) (Viwatpanich, 2015).People experiencing homelessness who drank alcohol in public spaces were more likely to have alcohol-related problems such as physical assaults (Yodkeeree & Laochankham, 2020).Children and youth experiencing homelessness were at risks of unemployment, game addiction, drug dependence, unsafe living, low self-esteem, behavioural problems, stigma, discrimination, and sexually transmitted infections (Khongmueang, Ekakun & Nilmoje, 2017;Muannadon et al., 2019).Sexual and reproductive health problems, including sexually transmitted infections, unwanted pregnancies and induced abortions, and limited knowledge of sexual diseases, were reported among adolescents experiencing homelessness (Narongsakputi, Ratchanakul & Nirattaradol, 2018).
Topic 3: healthcare and social services Different issues related to healthcare and social services were reported.The main focuses included barriers to services, management, and interventions.
Barriers to access to healthcare and social services included payment, documents for health insurance and social welfare, transportation, perception of receiving sub-standard care, healthcare providers' disrespectfulness, discrimination, and social stigma (Thienwiwatnukul, Ngamthipwatthana & Phattharayuttawat, 2020;Yodkeeree & Laochankham, 2020).One study highlighted the challenges of relevant public agencies to provide care for people experiencing homelessness, which included human resources (e.g., non-healthcare workers' knowledge) and management (e.g., lack of communication among relevant agencies) (Piamsap & Laochankham, 2020).
A study showed the roles of the government sector in caring for people experiencing homelessness in Nakhon Sawan Province, which included screening unit, analysing problems, evaluating target groups, and coordinating referrals to relevant agencies (Sattayawatee, Anuttaranggoon & Promwichai, 2021).To improve the quality of life of people experiencing homelessness, providing comprehensive support (e.g., healthcare services, housing, employment, education) and protection of rights and social welfare without discrimination were recommended (Khutkhong et al., 2020).One study reported policy aspects, personnel aspects, and collaborative aspects as challenges to prepare people with psychiatric disorders before returning to the society (Tuancharoensri & Nunnuan, 2020).Another study identified risk management of orgnisations, including internal (e.g., human resource) and external risks (e.g., legal aspects) for protection of people experiencing homelessness (Luangsurin, Metiyothin & Wiroonratch, 2019).
One study presented the development and effectiveness of a learning curriculum for children experiencing homelessness, and the results showed the improvement of several domains, including life skills (e.g., self-care, hygiene) (Srisung & Srivichaimool, 2018).A study assigned empowerment programmes to prevent sexually transmitted infections and found the significant improvement of the scores of sexually transmitted infection preventing behaviours (Houysai, Rutchanakul & Kongvattananon, 2015).

DISCUSSION
This scoping review identified 19 studies with regard to health-related issues of people experiencing homelessness in Thailand.Three topics (health status, causes of homelessness and effects of homelessness on health, healthcare and social services) were summarised from the included studies.Several studies illustrated mental health, physical health, and health behaviours among people experiencing homelessness.Homelessness affected people's lives as the bidirectional interactions.Homelessness was both a cause and an effect of health problems.People experiencing homelessness had some barriers to access to healthcare and social services (e.g., health insurance, social welfare, financial difficulties, social discrimination and stigma).A number of studies explored the roles and needs of the government sector to provide care for people experiencing homelessness.Two studies showed the effectiveness of educational and health promoting programmes to improve health of children and youth experiencing homelessness.
Studies in Thailand revealed the connection between mental health and people experiencing homelessness.Psychiatric conditions, including mood disorders, psychosis, alcohol and drug dependence, were reported as important mental health issues.This finding was consistent with studies conducted in other countries (Carrillo Beck et al., 2022;Doran et al., 2018;Onapa et al., 2022).There were limited studies regarding physical health among people experiencing homelessness in Thailand.In this review, the outstanding concerns included accidents, injuries, and health conditions associated with hygiene.Previous literature shared the similar trends of physical health among people experiencing homelessness (Fazel, Geddes & Kushel, 2014).Sexually transmitted infections were found to be a main focus among some studies in this review.The high prevalence and vulnerability of sexually transmitted infections in people experiencing homelessness were also reported in studies from other regions of the world (Gonçalves Barbosa et al., 2023;Segala et al., 2024;Williams & Bryant, 2018).A variety of health-risk behaviours, including risky alcohol use, heavy smoking, and illicit drug use among people experiencing homelessness were commonly reported, which were in line with other studies in Thailand (Padilla et al., 2020;Smith-Grant et al., 2022).In contrast, physical and sexual abuse were uncommonly reported in Thai studies.
Several studies from Thailand demonstrated homelessness as the cause and also the consequence of health-related problems.From social health perspective, family issues (e.g., domestic violence, family breakdowns, unsafe living conditions) are some evidenced causes of being homeless (Karabanow, 2008;van den Bree et al., 2009).Considering neuropsychiatric conditions, mental illnesses and cognitive impairment were reported some causes of homelessness in Thai studies (Khutkhong et al., 2020).Previous evidence also supported this finding (Stone, Dowling & Cameron, 2019).On the other hand, homelessness affects physical, mental, and social health.This was in line with studies in other countries (Bower, Conroy & Perz, 2018;Duke & Searby, 2019;Liu, Chai & Watt, 2020;Nanjo et al., 2020).Most studies conducted in Thailand revealed the negative health conditions among people experiencing homelessness.In contrast, a study described a majority of people experiencing homelessness perceived that they were happier than the general population (Viwatpanich, 2015).However, this result was collected by interviewing the study participants, and it was perspective, not compared to the perception of happiness among the general population.
Most included studies in this scoping review focused on social services (e.g., documents for health insurance and social welfare) rather than healthcare services.The Thai studies emphasised the characteristics of and barriers to social services.Public policies or strategies to prevent homelessness were not found in the included studies.A few studies addressed barriers to healthcare such as health insurance and payment (Yodkeeree & Laochankham, 2020;Thienwiwatnukul, Ngamthipwatthana & Phattharayuttawat, 2020).These issues affected the access to healthcare services.Some studies focused on utilising mental health services among people experiencing homelessness in Thailand (Wongjongrungruaeng, Naowarat & Kaewyot, 2019;Piamsap & Laochankham, 2020).However, studies in Thailand did not focus on the spectrum of healthcare services, including health promotion, disease prevention, treatment, rehabilitation, and palliation (Boerma et al., 2014;Klinjun et al., 2022).The included studies in this review revealed the health status of people experiencing homelessness rather than the healthcare service utilisation.This reflected a lack of studies on the mechanisms of healthcare service utilisation among people experiencing homelessness in Thailand.
There were some strengths of this scoping review.First, the systematic search was performed in eight databases, including both international and domestic databases.The Thai language search was applied to the TCI database.This approach could improve the yields of search results for Thai literature.Second, this scoping review focuses on a broad range of health-issues to explore the existing evidence from different academic fields and identify the gap in knowledge.The research paradigm and values could contribute to a better understanding of the knowledge in this field.Third, the search included all types of study designs.This helped identify the characteristics of studies on people experiencing homelessness conducted in the Thai context.Four limitations were addressed.First, the search terms for the ACI and TCI databases were adapted for the suitability for the databases.Second, this scoping review was unable to summarise the overall quantitative data of studies (e.g., pooled prevalence of psychiatric disorders).Third, some of the included studies presented the perspectives of individuals who looked after people experiencing homelessness rather than those of the people experiencing homelessness themselves.This could introduce bias into this review.Fourth, the quality assessment of individual studies in this review was not conducted.As a scoping review, this process was not compulsory (Peters et al., 2021).

CONCLUSION
This review sheds light on the scope of health-related issues in people experiencing homelessness in Thailand.Studies in Thailand describe the characteristics of mental health, physical health, and health behaviours among people experiencing homelessness.Social behaviours and health problems have a connection with homelessness.Homelessness affects health and living conditions.Social services are described in a number of studies.However, healthcare services for people experiencing homelessness are not the main focus of studies conducted in Thailand.Most studies included in this scoping review are characterised as descriptive data.The analytic interactions and mechanisms of health-related issues among people experiencing homelessness are still limited.Future studies should focus on the interactions and mechanisms between homelessness and health, as well as barriers and facilitators to utilise healthcare services.